1. Field of the Invention
The present invention is directed to an x-ray computed tomography apparatus of the type wherein an annular anode is scanned by an electron beam to produce an x-ray beam which moves in a circular motion centered at the center of an examination region.
2. Description of the Prior Art
An x-ray computed tomography apparatus of the type described above, i.e., with electronic scanning of an annular anode, is disclosed in German OS 4 103 588. An especially fast scanning of an examination subject is possible with such a computed tomography apparatus, plus it has a low space requirement. A static guidance field that holds the electrons on the predetermined orbit and a dynamic deflection (kink) field that deflects the electrons onto the annular anode at the desired location are required for guiding and deflecting the electron beam. In the known x-ray computed tomography apparatus, only a scanning of less than 360.degree. is possible because of the structural design, particularly of the guidance and deflection system.